My neighbor (cute female) has a 94 F-150 with the 5.0 liter eng.
She was complaining of the eng dieing when she let off the gas at freeway speed. Problem got worse and we were able to duplicate the stalling by holding eng at abt 2000 RPM, and letting off the gas quickly. It would die every time.

I pulled the throttle body, removed the TPS and idle air control.
Cleaned the throttle plates and re-assembled with a new TPS.(it was giving TPS codes) The problem got better but would almost die when letting off the gas quickly. I adjusted the min idle speed, and it seemed a lot better. I had noticed the idle air control (or whatever Ford calls it) looked pretty gunked-up.
A friend of mine told me they have plastic inside and attempting to clean with carb cleaner would mess it up.
Anyway, cute neighbor bought a new idle air control a week later and I installed it last night.

I now want to re-adjust the min idle screw back to where it should be.
How do I close the idle air control so I can adj the min idle screw?
Can I simply unplug it with eng running, or do I somehow have to drive it closed?

 

ttt

 

I am fairly certain there is no Idle speed adjustment on that 5.0. If you just unplug the iac while it is running it will just stay wherever it was when it was unplugged it will not close.

 

i Agree with Silver! Ultimately, the computer tries to control idle to a preprogrammed level - 672 rpm. The computers have some ability to 'learn' and adjust to new conditions/equipment. But some computers seem to be more resilient than others at continually searching for that lower idle. Drilling a hole in the throttle plate simply allows more air through which theoretically increases idle speed. However, at the same time the idle solenoid will allow less air through to try and slow things back down. It's that constant battle that contributes to idle surge. I wouldn't drill a hole - the same thing should be able to be accomplished by turning the throttle stop a bit so you slightly open the throttle plate - this also allows more air past - like lightly keeping your foot on the gas. However, when you adjust the throttle stop, you also need to check your TPS setting. Disconnect the idle solenoid electrical connection. Turn the throttle stop screw until you reach the idle speed you want. Put your digital voltmeter across the black and green wires on the TPS with the ignition on. It should be between .85 and .95V. If it's higher or lower - AFTER you set the idle speed where you want it, loosen the philips screws that hold it in and turn it slightly til you get the voltage reading above. You can also drill out the 2 screw holes to get better adjustment! You may have to take it off and elongate the mounting holes to get enough range of motion to make the adjustment. Once you've got it idling where you want it and have your TPS reset, shut the car off and disconnect the battery for a few minutes and turn your headlights on to completely discharge any power in the system. This will clear your computer's short term memory. Reconnect the idle solenoid, and go for a drive. Drive it for a day or 2 before you try anything else - this will give the computer a chance to try and re-learn. Don't set it above.98 or the trim value will be low and not right!

 

One more thing: If the car wont idle with the IAC disconnected then it wont idle with it connected! Rather then clean it just get a new one!